﻿//https://leetcode.cn/problems/remove-nth-node-from-end-of-list/?envType=study-plan-v2&envId=top-100-liked

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* removeNthFromEnd(ListNode* head, int n)
    {
        ListNode* temp = new ListNode(0, head);
        ListNode* fast = head;
        ListNode* slow = temp;
        while (n--)
        {
            fast = fast->next;
        }
        while (fast)
        {
            fast = fast->next;
            slow = slow->next;
        }
        slow->next = slow->next->next;
        ListNode* ret = temp->next;
        delete temp;
        return ret;
    }
};